Lecture: "Ammonia decomposition on lithium imide surfaces: A new paradigm in heterogeneous catalysis"

Professor Michele Parrinello is a Guest Lecturer of the Joshua Jortner Distinguished Lectures in Chemistry endowed by Raymond and Beverly Sackler for the academic year 2022/2023. 

Abstract:

The development of efficient catalysts is key to a green economy transition. In this respect, it suffices to mention the need to devise an energy-efficient production of hydrogen or an economical and environment-friendly CO_2 sequestration process. However, the large-scale production of chemicals often takes place under extreme conditions of temperature and pressure, so extreme in fact that both simulations and experiments are difficult or impossible. This challenges the conventional picture of catalysis in which a special static configuration of atoms is responsible for the catalytic activity.  

Based on state-of-the-art simulations that take advantage of machine learning methodologies, we put forward a different picture. Namely, we associate the catalytic activity with a change in the physical state of the interface. Such a change can be induced for instance by the temperature or by the reactants themselves. We exemplify this behavior in the catalysis of ammonia by iron surfaces and the cracking of ammonia by the 〖Li〗_2 NH ionic compound. The design of such a catalytic competent interfacial steady state is suggested as a strategy to design new, efficient and stable catalysts.